Really this answer depends on your type of knife. If you use a German/ French knife (i.e. a knife that has thick spine) you can use any type of steel, be it metal, ceramic, glass, diamond coated. If you use Japanese steel (i.e. thin spine) you should not hone your knives (If you are using brands like Shun, Global, these are good knives, but mass-produced, so any steel type, other than glass should be acceptable). Considerations: metal steels will not sharpen your knife, but they will bring them back to true (this means back into alignment, as using the knife can cause the edge to bend slightly). Ceramic, Diamond coated, and glass steels are harder than your knife's metal and will remove metal from the blade. The benefit being it will actually sharpen your knife to some extent and do it quickly, but it will also decrease the knife's life. For day-to-day honing I would recommend the F. Dick Multicut Sharpening Steel. It is the best metal steel you can buy. It is expensive (~$100), but will last longer than your knife and does a great job at bringing knives back to true. To be honest though, any 12" metal steel will perform adequately, it is just the fact the F. Dick model just does it better.

Thanks, everyone. Boulangere, to your point, that was a great suggestion. The next time I went to Piedmont Grocery (my favorite store, where I buy quite a bit of my meat, and where I shop three times a week, at least) one of the butchers who's been there for years and knows me well said he likes the Forschner. I asked him where I could find one, and he directed me to a small knife shop on Telegraph, half a block from Betty's Bakesale (near 51st St), with whom the Piedmont Grocery butcher shop has been doing business for years. Haven't made it over there yet, but am looking forward to it. ;o)